A Guide To Orthotic Therapy For Adult-Acquired Flatfoot

Start Page: 48
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Author(s): 
Paul R. Scherer, DPM

   They compared the efficacy of insole orthoses and gauntlet ankle braces by evaluating their stabilizing effect on the motion of the medial longitudinal arch and calcaneal position of six cadaveric subjects.12 Researchers simulated a flatfoot condition by sectioning the structures of the medial arch. They tested each specimen with six different devices: UCBL foot orthoses, a molded polypropylene AFO, an Arizona-type gauntlet and three prefabricated stirrup-type braces. The UCBL in-shoe orthoses provided superior restoration of both arch and hindfoot kinematics. The molded polypropylene AFO performed poorly. The Arizona-type gauntlet restored the height of the midfoot but had little effect on the orientation of the calcaneus. The prefabricated stirrup-type braces were basically ineffective in stabilizing the hindfoot and arch.

   Interestingly, in another study performed in 2003, 95 percent of patients treated conservatively with restrictive devices for adult-acquired flatfoot reported a significant reduction in symptoms.13

   The gauntlet brace that is recommended for stage III adult-acquired flatfoot must be made to specific parameters in order to have a positive clinical outcome. Accurate casting is absolutely essential if the brace is to be comfortable and produce good patient acceptance and tolerance.

   The inability of the foot in stage III to reach 90 degrees with the leg poses, in most patients, a unique challenge. Often, arthritic lipping and ankle joint degeneration affecting the anterior talocrural joint produce an osseous equinus. The laboratory fabricating the brace must know that the foot does not reach the 90 degrees standard and should accommodate for this in the cast correction.

   The resulting gauntlet brace for this equinus patient with adult-acquired flatfoot will be slightly plantarflexed and one must accommodate this deficiency by adding a lift in the shoe or tilt on the sole of the shoe. Allowing the patient with an equinus deformity to remain plantarflexed without raising the heel with extra material to support the heel will cause the anterior aspect of the leg to experience great pressure against the front of the brace at midstance as the tibia attempts to pass over the foot. Making the brace more rigid and confining to relieve this pressure redirects the sagittal plane motion requirement proximally and may produce a genu recurvatum.

   Since the gauntlet-type brace immobilizes the ankle, subtalar and midtarsal joint, it prevents motion in the sagittal, frontal and transverse planes. This is all beneficial for reducing symptoms but the patient must find an alternative to sagittal plane motion in order to ambulate.

   Rather than transfer this sagittal plane motion to the knee, which accepts it poorly, one can transfer motion to the shoe-ground interface with the use of a midsole rocker. A pedorthist who is familiar with rocker placement can easily add this rocker to most shoes. The ideal placement is a 60/40 rocker. Many extra-depth shoes are manufactured with this rocker sole.

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